全波形反演(FWI)是一种较为精确的速度建模方法,但是在缺少低频和背景速度场不准确的情况下,容易引起周波跳跃现象.为了快速构建三维背景速度模型,提出了一种新的平面波编码策略,即构建新的平面波形态——锥面波,通过控制射线参数,实现多尺度锥面波编码全波形反演方法(CFWI),达到反演背景速度模型的目的.通过动态锥面波编码策略,仅用少量的平面波,就可以实现背景速度场的建立,大大降低了反演的计算量.将动态锥面波反演方法应用于三维洼陷和逆冲速度模型测试,结合多震源的FWI(MFWI),对于较差的初始模型和不含低频地震数据,能够准确地反演出速度模型.

川东北普光地区长兴组生物礁具备广阔的勘探潜力.文中对比了普光和元坝地区生物礁的生长模式,分析了生物礁及储层的地质特征,总结了礁相白云岩储层的纵横向分布规律.在此基础上,利用测井资料、地震资料,进行生物礁模型地震正演,确定生物礁及储层的地震相识别模式;采用古地貌分析确定储层发育的有利沉积相带,并通过沉积相带的展布和适宜的时窗选取规避不利岩性(泥灰岩)的干扰,再使用相面法、属性分析、波阻抗反演对有效储层进行精细预测,建立了一套适用于普光地区的生物礁储层地震预测方法,定量预测了普光地区长兴组生物礁储层的分布,认为生物礁储层垂向上主要发育于礁盖,横向上主要分布在台地边缘的狭窄条带上.预测结果与钻井资料、礁相储层分布规律相符,证明了方法的有效性.

目前基于字典学习的三维地震数据重建方法通常采取二维逐切片重建的策略,这种重建方式忽略了切片间的相互联系,未能充分运用地震数据各个方向上的连续性约束.为此,提出了一种三维联合重建方法——快速结构字典学习三维数据重建方法.该方法在压缩感知理论框架下,利用快速结构字典学习算法训练训练集,产生三维自适应字典;然后利用三维自适应字典、观测矩阵以及正则化正交匹配追踪算法对数据进行高精度重建.模型数据和实际数据的重建结果表明,该方法能够恢复地震数据的细节特征,具有重建精度高、保幅性良好的优点.

"两宽一高"地震勘探面向更为复杂的油藏描述,反演成像成了必要的技术手段,但数据中的噪声会严重影响地震波反演成像的质量,因此针对"两宽一高"地震数据研发有效且实用的去噪方法十分必要.在Bayes估计理论框架下,当信号满足线性(可预测性)假设且噪声满足高斯分布时,在均方误差或最小平方误差最小准则下估计最佳预测滤波器可进行有效滤波.同时随着地震数据维度的升高,高维信号的空间结构信息更丰富,因此在高维数据空间设计滤波器能够更有效地提高滤波器的信号预测能力,并且更好地压制噪声.首先将基于AR(自回归)模型的f-x域预测滤波器(前向预测滤波器和后向预测滤波器)修改为Wiener中心预测滤波器;然后在最小二乘意义下对高维地震数据进行多级Hankel矩阵排布构建法方程;再求解法方程得到Wiener中心预测滤波器,最后实现高维地震数据的Wiener中心预测滤波.为满足高维数据的局部线性假设,对复杂波场的地震数据,采用局部取窗的方式进行Wiener中心预测滤波去噪.合成理论数据和实际数据的测试结果说明该方法能够在地震数据中存在弱线性同相轴、振幅值缓慢变化以及信噪比相对较低的情况下较好地压制随机噪声,提高数据的信噪比,故该方法具有较强的实用性.

Compared with the conventional migration method, least-squares reverse time migration (LSRTM) has a lot of advantages, such as higher imaging resolution, amplitude preservation and amplitude balance and so on. But, the L2 norm based LSRTM algorithm is very sensitive to noise, especially when the data contains outliers. Compared to L2 norm, Student’s t distribution has better robustness. We extend the Student's t distribution to the LSRTM algorithm. In addition, multi-sources inversion is an effective way to reduce the computational cost. However, it often generates crosstalk noise. In this paper, we use L1 norm sparse regularization constraints with K-SVD dictionary learning to suppress the crosstalk noise caused by phase encoding. Theoretical models and field data processing verify the effectiveness of the algorithm and suitability for complex models. Presentation Date: Tuesday, September 17, 2019 Session Start Time: 1:50 PM Presentation Start Time: 3:30 PM Location: Poster Station 10 Presentation Type: Poster

谱反演作为近年出现的一种反演方法,不依赖测井资料等先验信息,只需利用地震数据本身的频谱信息就可反演地层稀疏反射系数,并能突破常规地震资料调谐效应导致的分辨率极限.研究发现,时间域的奇偶脉冲分量与频率域的正余弦分量具有等价性.基于此,本文提出一种直接在频率域利用地震数据谱的正余弦分量进行协同反演的方法,得到高分辨率稀疏反射系数序列.理论模型试验和实际资料应用结果表明,利用该方法能取得精确的反演结果,能识别原始地震剖面上无法分辨的薄层和小尺度地质体.

In order to solve complicated faults imaging problem of the Dongpu oilfield,the authors utilized multi?step reverse time mi?gration method and realized GPU accelerate parallel algorithm for overcoming the low compute efficiency disadvantage of RTM.The GPU accelerated multi?step reverse time migration method was successfully applied to complicated faults imaging processing. The RTM ima?ging result of Qianliyuan 3D data proved the technological advantage of RTM for complicated small faults imaging and Lanliao dip?angle faults imaging.Migration efficiency analyses demonstrate that RTM based on GPU accelerate algorithm can effectively improve the com?putational efficiency by 75 times.

脆性指示因子是评价泥页岩储层的一个至关重要的参数.在勘探阶段,高脆性泥页岩发育区常发育裂缝,易形成产能,有助于开发区域优选;在开发阶段,脆性指示因子有效预测能为水平井部署、井身设计以及压裂改造提供重要的依据.目前国内利用地震方法预测脆性指示因子空间展布的研究并不广泛.文中利用地震叠前反演得到弹性模量与泊松比2个关键参数,进而预测脆性指示因子.预测结果与已知井的情况符合较好.

现今逆时偏移的应用面临海量数据存储及计算量巨大的问题.本文应用震源重构方法解决了逆时偏移互相关成像条件需要的海量存储问题,引入GPU Kernel解决逆时偏移计算效率低的问题.在此基础上,本文建立了一套基于GPU加速的叠前逆时偏移成像方法,并成功地应用于四川盆地A复杂区块.

There are many difficulties in reverse time migration applications for nowadays seismic exploration, storage and computations of the mass data may be the top ones. In this paper we use source reconstruction method to reduce mass storage brought by cross-correlation imaging condition, and introduce GPU kernel to improve computation efficiency. And based on these, we build a GPU accelerated reverse time migration method, which successfully applied in Block A, a complex area in Sichuan Basin.

As traditional AVO techniques can not be used to visually evaluate the hydrocarbon potential of the reservoir,so the extracted AVO attributes are not well in accord with the gas-bearing properties of the actual wells.This paper proposed AVO fluid inversion to analyze the gas-bearing properties in northeastern Sichuan.This technology was successfully applied in the fourth member of Xujiahe Formation in one area of northeastern Sichuan.The result was consistent with case of actual wells,and good results have been achieved,which affords a favorable evidence for reservoir prediction in this area.

By taking the drilling core samples from Dongpu Depression for examples,the acoustic characteristics of dried rock samples and rocks filled with porous fluid were measured at the conditions of simulated well temperature and pressure in the laboratory.Eight acoustic and elastic parameters such as the pressure and shear wave velocity,density,Poission's ratio,Yang's modulus,elastic modulus,shear modulus as well as bulk modulus of the sandstone were measured at the interval of 20% water saturation.The relationship of the pressure with P and S wave velocity,the Vp/Vs ratio,Poission's ratio as well as the elastic parameter is fitted for No.1 sample.The relationship of the P and S wave velocity,the Vp/Vs ratio,Poission's ratio and elastic parameters of rocks under different conditions of pressure and temperature changing with water saturation are fitted for No.2 sample during water-oil displacement.The result provides fundamental data for the pre-stack seismic inversion,lithology identification and fluid detection for Dongpu Depression.The results also provide petrophysical evidence for the future geological and geophysical research in the area.

The complex relief surfaces in western China challenge correct seismic imaging of them.The numerical simulation and processing analysis of the relief surface model were conducted,and the problems existed in the seismic imaging under relief surface conditions and solutions were discussed,including realization of pre-stack reverse time migration based on relief surfaces and processing of the model data.Compared with conventional processing approaches and pre-stack depth migration based on floating datum,this method can be effectively applied to the northern Shaanxi with complex landforms.

Pre-stack elastic impedance inversion involves the calculation of elastic impedance curve,while the conventional calculations are based on the assumption that K is a constant,but the assumption does not match with the actual situation,which results in the deviation in calculating elastic impedance curve and extracting the lithology parameters.Therefore,we introduced K scan method to optimize the selection of K.The method includes three steps.Firstly, different K was selected to compute elastic impedance.Then,the elastic impedance was transformed into reflectivity.Finally,the difference of the reflectivity obtained from the second step and accurate Zeoppritz equation was calculated,and the minimum difference was the optimal K.application on theoretical model and actual logging curve show that the method can be used to select best K and has good applicability.

Seismic exploration accuracy meets higher and higher requirements since the exploration targets in Dongpu Sag tend to be more subtle and complicated.For this,this paper puts forward a new method for acquiring horizon velocity based on joint inversion of stack velocity and migration velocity,improving the accuracy of velocity calculation.Through study on methods for establishing velocity field,the technology of establishing velocity field on the basis of combining such information as seismic velocity,logging,drilling and structural horizon is developed,and the velocity field reflecting the macroscopic law of velocity distribution is obtained,which is in good agreement with the well.Integrating the concept and application of seismic velocity,this paper defines the correlation of various types of velocity and its applicability,providing a complete velocity field solution for different phases of seismic exploration.Based on coordinate positioning and unified format transformation of seismic velocity data,the velocity base of all over Dongpu Sag is established,supporting seismic imaging,variable velocity mapping,and prediction of regional formation pressure technically,and yielding good results.

The conventional 3D seismic geometry designing is based on the horizontally stratified medium presumption, its main objective is to obtain regularly sampled stacking dataset, which can be used to image the geological target through post-stack migration. Different from post-stack migration in which the regular post-stack data volume is used, the pre-stack migration uses irregular offset datasets. The irregular spatial sampling of the 3D geometry could probably result in severe migration noise, which then may partially decrease the effect of the pre-stack migration. Designing the 3D geometry which meets the requirement of pre-stack migration has great significance by fully making use of the advantages of the pre-stack migration and raising the imaging accuracy. The new geometry designing method was introduced in this paper, based on the evenly sampling and bin attribute consistence principle the geometry template was designed, good spatial samples were acquired, the designed geometry were gradually optimized by using focus beam, pre-stack migration response, forward modeling, wave field illumination and other techniques, at last the geometry which could meet the requirement of pre-stack migration and could resolve geological problem was obtained. The new method was applied in QK survey in Dongpu Depression and the excellent results were achieved in the survey.

When there are not enough shot points and samples, pre-stack migration will result in severe migration noise, so as to restrict the imaging accuracy in the pre-stack migration. Base on the scatter point pre-stack migration response technique and ray tracing modeling technique, the influence of geometry type, the swath width and the swath rolling distance to the pre-stack migration effects was analyzed in this paper. The analysis results show that the orthogonal geometry is apt to achieve better imaging results compared with oblique and brick-wall geometries. If the spatial sampling density and the swath rolling distance keep the same, the wider swath is apt to reduce migration noise, if the spatial sampling density and the swath width are fixed, the smaller swath rolling distance is favorable for better imaging results.

本文探索了叠前和叠后分频处理方法,提出了相应处理流程.叠前分频处理主要是通过针对不同频段分别处理而改善噪音衰减的保真度,从而提高数据处理的精度.叠后分频处理则主要用于提高地震资料分辨率,增强地震资料识别小尺度地质体的能力.本文通过一个楔状模型分析了分频处理的效果,分频处理结果提高了对薄层的分辨能力.通过实际地震资料的叠前和叠后分频处理,提高了地震剖面质量,实现了对含有砂体的识别和追踪.

Imaging of complicated geological structure is one of the major difficulties in the field of seismic exploration,and the main factor of imaging is migration of the velocity field.Therefore,constructing accurately the migration velocity field is not only the core of high precision imaging,but also the nexus between seismology and geology.In fact,the accuracy of velocity that is picked with the conventional method is rather low under the large offsets,dipping or bend interfaces,pre-salt and deep multilayered medium.As a result,it reduces the accuracy of seismic imaging as well as the reliability of imaging and interpretation.To solve this problem,a new method of PSTM velocity field building is adopted,that is,initial velocity of migration acquiring,bi-spectral high density velocity analysis and anisotropy PSTM.The practical result has proved its good effect and the real accuracy of migration has been increased much.

The Dongpu depression is a faulted basin with versatile depositional environment,broken fault-blocks and complicated structures.Its local structure is controlled by faults.There are major lateral velocity alternations because of different buried depths of contemporaneous strata in the two sides of faults.But time migration is unable to work out this problem,so anisotropic pre-stack depth migration has been applied to this area,and high density velocity analysis is ombined with acoustic logging data.The results show coincidence of seismic and drilling with anisotropy PSDM.